Zipper stringer

ABSTRACT

A flexible stringer of integral construction for slide fasteners is shown. The flexible stringer includes a flat flange member and a bead. The bead cross-section is shaped to conform to the area defined by the closure arms of the fastener elements emplaced upon it. The stringer shown includes a substantially flat inner surface which extends outwardly at substantially right angles from the flange. A second right angle is defined at the juncture of the inner and outer surfaces of the bead. In the preferred embodiment the bead comprises a half cylindrical volume symmetrically positioned with respect to the flange and has a cylindrical void located symmetrically within it. A firm holding force between the stringer and the conventional fastener members is obtained.

United States Patent [191 Goldstein 541 ZIPPER STRINGER Barry Goldstein, Rockville Centre, NY.

[75] Inventor:

[73] Assignee: Stagg Zipper Corp., Brooklyn, N.Y.

[22] Filed: Apr. 13, 1971 [21] Appl. No.: 133,617

[52] US. Cl. ..24/205.l 3 R, 24/205.16 R

[51] Int. Cl. ..A44b 19/06 [58] Field of Search ..24/205.13, 205.16

[56] References Cited UNITED STATES PATENTS 1/1942 Corner ..24/205.13 1/1937 Sundback.

Italy ..24/20s.13 Italy ..24/20s.13 R

Primary Examiner-Bernard A. Gelak Attorney-Curtis, Morris & Safford [57] ABSTRACT A flexible stringer of integral construction for slide fasteners is shown. The flexible stringer includes a flat flange member and a bead. The bead cross-section is shaped to conform to the area defined by the closure arms of the fastener elements emplaced upon it. The stringer shown includes a substantially flat inner surface which extends outwardly at substantially right angles from the flange. A second right angle is defined at the juncture of the inner and outer surfaces of the bead. In the preferred embodiment the bead comprises a half cylindrical volume symmetrically positioned with respect to the flange and has a cylindrical void located symmetrically within it. A firm holding force between the stringer and the conventional fastener members is obtained.

4 Claims, 3 Drawing Figures PATE v.3.Y29 m5 NTEL 3.735454 1 ZIPPER STRINGER This invention relates to flexible fasteners and more particularly to fasteners commonly called zippers. More specifically, this invention relates to a flexible elastomeric stringer for slide fasteners upon' which the slide fasteners are emplaced.

In conventional slide fasteners, it is conventional practice to provide a fabric stringer on either side of an opening in an article or in a garment and to emplace a series of interlockable slide fastener members upon it. Typically the stringer is a flat tape having a beaded edge which the fastener members grip. A significant disadvantage of conventional fabric zipper stringers stems from the inherent weakness of the fabric bead. It has been found that the slide fastener members pull away from or rip the fabric bead or otherwise move from their initial position on that bead. This results in poor fastener closure or failure of the fastener under strain. A further disadvantage of the fabric stringers and fabric beads is that a stitching step is required to affix the bead to the flat stringer tape. This step increases manufacturing costs considerably.

Severalsolutions have been proposed for solving this problem in slide fastener design, among them increasing the width of the fastneer members, i.e. their dimension in the longitudinal direction of the stringer. This is undesirable, however, in many applications because the fastener becomes bulky and heavy or it becomes difficult to achieve a tight closure. Providing reinforcing stitching at the interface of the bead and the flat stringer tape is an acceptable expedient; however, it still has the functional and cost disadvantages mentioned above.

One suggested stringer design for slide fasteners is an integral stringer tape and bead formed from an elastomeric material. Thus, for example, U.S. Pat. No. 2,287,323 discloses a molded stringer having a round beaded portion upon which the several fastener members are emplaced. Where the stringer is formed, as is suggested, from molded rubber, it is sufficiently flexible to accommodate the movements of the fastener members as the connecting sliders move and it also is relatively inexpensive to manufacture by extrusion techniques.

A disadvantage of these stringer constructions is that the holding force between he stringer bead and the closure arms of the slide fastener members is not sufficient to prevent movement of the fastener members on the stringer. This problem is manifested by the tendancy of the fastener members to pull away from the stringer head or to slide therealong. Any displacement of a fastener member from its position may render the entire fastener inoperable or the removal of one fastener member from the tape can seriously weaken the holding power of the fastener.

It is thus the primary object of this invention to provide a flexible stringer of integral construction for slide fasteners which avoids the above-mentioned problems heretofore encountered.

It is a further object of this invention to provide an easily manufactured, flexible stringer for zippers, upon which metal or plastic fastener members can be emplaced and which provides a firm emplacement for those fastener members with sufficient holding power to prevent displacement of the fastener members from the bead of the stringer.

It is still a further and related object of this invention to provide a flexible stringer upon which metal fastener members can be emplaced with conventional manufacturing equipment and without the need for costly additional manufacturing steps.

These and other objects of this invention are achieved in a flexible stringer of integral construction for use primarily in zippers which includes a flat flange member for attachment to the side of an opening .in an article and which also includes a head at one end of the flange member and about which a series of slide fastener members are emplaced. The improvement in this flexible stringer resides in the design of the bead sothat its area in cross-section is the same or largerthan the area defined by the closure arms of the fastener members and so that its shape in cross section is the same as that defined by the closure arms.

In the embodiment described in detail below, .the bead includes a substantially flat inner surface extending outwardly at substantially right angles from the flange portion of the stringer. The flat inner surface extends outwardly from the flange portion of the stringer to the maximum lateral diameter of the bead and there joins the outer surface of the bead at substantially right angles. The outer surface includes a curved portion 'desirably having a semi-circular perimeter in cross section view. The head comprises a half cylindrical volume symmetrically positioned with respect to the flange member.

In a further improved embodiment of this invention, thebead portion of the flexible stringer includes a void space. The void space permits the inward compression of the bead upon emplacement of the slide fastener members. Once the slide members are emplaced on the bead, the compressive forces are partially released and the bead locks itself within the closure arms of the fastener member. Desirably, the void is symmetrically located within the bead volume and the ratio of-the volume of the void to the volume of the head is from 1:5 to 4:5. The invention is further disclosed below in connection with the drawings.

In the drawings:

FIG. 1 is a front view of a flexible stringer of this invention having a conventional fastener member emplaced on it.;

FIG. 2 is a section view taken along lines 2-2 of FIG. 1; and

FIG. 3 is an end view of a preferred stringer according to this invention.

In FIG. 1 reference numberal 10 refers generally to the stringer. Reference numeral 12 refers to a flat flange member which is suitable for attachment to the side of an opening in a garment or in an article. Where the flexible stringer is comprised of an elastomeric material the flange member may be directly heat bonded to the fabric at the side of an opening. Numeral 14 refers to a bead at the upper end of flange member 12. Bead 14 includes flat inner surface 16 which extends outwardly at a substantially right angle designated b referance numeral 18 from flange member 12. The outer surface of bead 14 is designated by reference .numeral 19. Outer surface 19 includes curved portion 20 having a semi-circular perimeter in the crosssecti on view of FIG. 2. Outer surface 19 also includes ashort straight length 22 which joins inner surface 116 at the substantially right angle designated by reference numeral 24.

Numeral 30 refers to a conventional slide fastener member which is typically comprised of metal and which is firmly emplaced around bead 14 by techniques well known in the art. Fastener member 30 includes lower locking arms 32 whose inner surfaces firmly abut against the inner flat surfaces 16 of bead 14. Member 30 likewise includes side arms 34 whose inner surfaces mate with the flat and the rounded portions of outer surface 19 of bead 14. The inner juncture between the lower arms 32 and the side arms 34 of fastener member 30, is a right angle which mates with right angle 24 be tween the inner and outer surfaces of bead 14. Thus, the shape defined by the closure and side arms of closure member 30 is the same as that of bead 14 in cross section.

By providing mating surfaces as is seen in the drawings, between the stringer bead and the fastener member and more particularly by providing the right angles shown, a very firm interlocking is achieved between the fastener member and the stringer. It has been found that the holding force developed between the fastener member and the shaped bead is sufficiently great to prevent movement of the member on the stringer. The fastener members do not move either along the stringer nor are they displaced from the stringer. Accordingly, substantially more satisfactory fastener performance is obtained.

' In FIG. 3 numeral 40 refers to the flange member of a preferred stringer of this invention. Reference numeral 42 identifies the bead having inner surface 44 and outer surface 46 which are essentially as described in connection with FIGS. 1 and 2 above. In the stringer of FIG. 3, however, bead 42 includes a void volume 48 within it. Void volume 48 allows bead 42 to contract when fastener members such as those shown in FIGS. 1 and 2 are emplaced upon it. Thus, the bead can be made slightly larger than the area difined by the closure arms of the fastener members. This will maintain the bead in compression with the result that a very firm holding force is established. Desirably, the ratio of the volume of void 48 to the total volume of the bead is in the range of from 1:5 to 4:5. The choice of the actual ratio of volumes will, of course, depend on the service of the fastener, the elastomeric materials of the stringer bead and other factors which will be appreciated by those skilled in the art. The void volume is desirably symmetrically located within the bead volume. The flexible stringers of this invention may be formed from suitable elastomeric materials such as polyethylene, polyvinyl chloride, nylon, and polyester. Good results have been obtained by using polyvinyl chloride. cm What is claimed is:

1. In a flexible stringer of integral construction for slide fasteners including a flat flange member for attachment to the side of an opening in an article and a bead at one end of said flange member about which slide fastener members are emplaced, the improvement wherein said bead comprises a half cylindrical volume integral with a rectangular volume, the latter being symmetrically positioned with respect to said flange, said bead including a cylindrically shaped void located symmetrically within said bead volume to permit contraction of said bead upon emplacement of said slide fasteners.

2. The flexible stringer of claim 1 wherein the ratio of the volume of said void to the volume of said bead is from 1:5 to 4.5.

3. The stringer of claim 1 formed of polyvinyl chloride.

4. In a flexible stringer of integral construction as recited in claim 1, the further improvement wherein the cross sectional area of said bead is larger than the area defined by the closure arms of the fastener member, the shape being the same. 

1. In a flexible stringer of integral construction for slide fasteners including a flat flange member for attachment to the side of an opening in an article and a bead at one end of said flange member about which slide fastener members are emplaced, the improvement wherein said bead comprises a half cylindrical volume integral with a rectangular volume, the latter being symmetrically positioned with respect to said flange, said bead including a cylindrically shaped void located symmetrically within said bead volume to permit contraction of said bead upon emplacement of said slide fasteners.
 2. The flexible stringer of claim 1 wherein the ratio of the volume of said void to the volume of said bead is from 1:5 to 4.5.
 3. The stringer of claim 1 formed of polyvinyl chloride.
 4. In a flexible stringer of integral construction as recited in claim 1, the further improvement wherein the cross sectional area of said bead is larger than the area defined by the closure arms of the fastener member, the shape being the same. 